And everybody understands that if one could clone a human, its personality would still be unique. If you could somehow clone a human and download all the memories of the original into the clone, you would have--for a brief time--the closest thing to an exact copy. But since the clone's world line would instantly diverge from the original, by tomorrow morning you would have two separate individuals. Amazingly similar, but unique.
This presupposes you could forcibly cause the duplicate to age to the original's age before the "download". If you make a clone, after all--you will get a baby.
--Boris